Reliability and validity of Six-Spot Step Test (SSST) in stroke survivors

BACKGROUND: The Six-Spot Step Test (SSST) was originally developed to assess walking ability while challenging balance during walking in patients with multiple sclerosis. It provides more comprehensive information on ambulatory abilities than several existing measures such as the Timed Up and Go test (TUG test), the Functional Gait Assessment, and the Dynamic Gait Index. To assess the advanced balance control ability of stroke survivors, we modified the SSST to serve this purpose. AIM: The aim of this study was to expand the current understanding of the psychometric properties of the SSSTusing healthy older adults and stroke survivors. DESIGN: This study adopted an experimental design. SETTING: University-affiliated neurorehabilitation laboratory. POPULATION: Atotal of 50 study participants, including 25 chronic stroke survivors and 25 healthy older adults, were recruited from the community. METHODS: The SSSTwas administered to the stroke survivors twice (day 1 and 2) with a 1-week interval. The Fugl-Meyer assessment for the lower extremities (FMA-LE), the Berg Balance scale (BBS), the limit of stability (LOS) test, the Timed Up and Go test (TUG test), and the Chinese version of the Community Integration Measures (CIM-C) were assessed on day 1 by random order. The healthy control group was assessed with the Six-Spot Step Test only on day 1. RESULTS: The SSST showed excellent inter-rater, intra-rater, and test-retest reliability (intraclass correlation coefficient >0.95, P<0.001). Significant correlations were found between SSST performance and the FMA-LE results (r=0.517, P<0.05), BBS scores (r=-0.531, P<0.05), and TUG test scores (r=0.828, P<0.001). The MDC in the mean SSST time for the affected leg and the unaffected leg in stroke survivors was 6.05s. The cutoff time was 10.11s (sensitivity, 80%; specificity, 92%) when kicking obstacles with the affected leg and 10.18s (sensitivity, 80%; specificity, 92%) when kicking obstacles with the unaffected leg. CONCLUSIONS: The SSST was a reliable test and showed a significant correlation with FMA-LE scores, BBS scores, and TUG test times in stroke survivors.